JP7389468B2 - Resistor - Google Patents

Description

The present invention relates to a resistor suitable for use as a resistor for an antifreeze heater of a water heater.

Conventionally, for example, in order to prevent the water pipe of a water heater from freezing, a resistor for a heater may be attached to the water pipe. As shown in FIGS. 1 and 2 of Patent Document 1, for example, this type of resistor has lead wires (55) and (57) placed inside a housing (11) of a ceramic case (10) at both ends. A resistor element (50) connected to the resistor element (50) is housed therein, and the housing part (11) is filled with liquid cement using liquid varnish as a filler (80).

Japanese Patent Application Publication No. 2017-004700

As mentioned above, conventionally, the storage part (11) was filled with liquid cement using liquid varnish as the filler (80) and left to air dry for about 24 hours to prevent air bubbles from forming. The problem was that it took a long time to complete.

Therefore, the inventor of the present application attempted to use powder cement instead of liquid cement. Powder cement is made by applying varnish to the surface of insulating powder, which is filled into the housing of a case, heated, melts the varnish, bonds the powder together, and then cools and hardens (solidifies). let When powder cement is used in this way, there is no need for long-term natural drying as with the liquid cement, so the time required to complete the product can be shortened. However, after hardening, the surface of the powder cement that adheres to each other is easily scraped, and if your fingers touch the surface of the filled and hardened powder cement, there is a risk that the powder that makes up the cement will be scraped off. Ta.

In addition, powder cement tends to have fine voids between mutually bonded powders, and there is also a risk that its waterproof performance and insulation performance will be inferior to that of liquid cement.

In addition, for example, when a lead wire is inserted into a recessed lead wire insertion part provided in a case, a gap may be created between the inner bottom surface of the lead wire insertion part and the lead wire, but the Since powder cement does not have viscosity, the powder cement does not enter the gap, and the gap remains as it is, and therefore there is a risk that the filling material may not be able to reliably waterproof and insulate the resistance element.

The present invention has been made in view of the above points, and an object thereof is to provide a resistor that can be reliably waterproofed and insulated.

The present invention is constructed by storing a resistance element in a resistance element storage part provided in a case, filling the resistance element storage part with a filler, and further pulling out a lead wire connected to the resistance element to the outside of the case. In the resistor, an opening for the resistance element housing is provided on the upper surface of the case, and a lead wire insertion groove is provided at least on one side of the case around the resistance element housing, and the opening for the groove is provided in the upper surface of the case. Apply a groove sealing sealant to the inner bottom surface of the lead wire insertion groove, insert the resistance element into the resistance element housing through the opening, and insert the resistance element into the lead wire insertion groove from the groove opening. The filler is filled into the resistor element housing with the lead wire inserted into the groove sealing material and the lead wire is placed on the groove sealing sealant , and the top surface of the filler on the opening side is filled with the filler. It is characterized by having a sealant applied to cover it.
According to the present invention, since the upper surface of the opening side of the filler filled in the storage section of the case is covered with the sealing material, it is possible to reliably prevent liquid or moisture from entering the storage section, and ensure waterproofing and insulation of the resistance element. can be maintained.
In particular, when powder cement is used as the filler, it is more effective since it cannot be said to have better waterproof properties than liquid cement.
Further, according to the present invention, since a groove-sealing sealant is applied to the inner bottom surface of the lead wire insertion groove, when the lead wire is inserted into the lead wire insertion groove, the lead wire can be easily and reliably inserted into the lead wire insertion groove. It can be brought into close contact with the groove-sealing sealing material, and the gap will not occur. This makes it possible to more effectively prevent liquid or moisture from entering the storage section.

In addition to the above features, the present invention provides that the filler is also filled in the lead wire insertion groove, and the sealing material is placed on the upper surface of the filler filled in the lead wire insertion groove on the groove opening side. It is also characterized by being coated with
According to the present invention, since the sealing material also covers the upper surface of the filler filled in the lead wire insertion groove, it is possible to more effectively prevent liquid or moisture from entering the storage section.

According to the present invention, a resistor can be reliably waterproofed and insulated.

FIG. 2 is a perspective view of the resistor 1 (however, a groove sealing sealant 85 is not shown). FIG. 2 is an explanatory diagram of a method for manufacturing the resistor 1. FIG. FIG. 2 is an exploded perspective view of the resistor 1. FIG. 4(a) is a perspective view, FIG. 4(b) is a sectional view taken along line AA in FIG. 4(c), FIG. 4(c) is a plan view, and FIG. 4(d) is a diagram showing the case 10. It is a BB sectional view of FIG. 4(c). FIG. 2 is an explanatory diagram of a method for manufacturing the resistor 1. FIG. FIG. 2 is an explanatory diagram of a method for manufacturing the resistor 1. FIG. FIG. 2 is an explanatory diagram of a method for manufacturing the resistor 1. FIG. FIG. 2 is an explanatory diagram of a method for manufacturing the resistor 1. FIG. FIG. 3 is an enlarged view of main parts showing the relationship between a lead wire 51 inserted into a lead wire insertion groove 15, a seal layer 15A, a filler 60, and a seal material 70. FIG.

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view of a resistor 1 according to an embodiment of the present invention (however, a groove sealing seal material 85 is omitted). Further, FIG. 3 is an exploded perspective view of the resistor 1. As shown in these figures, the resistor 1 stores a resistance element 40 in a resistance element storage part 11 provided in a case 10, and fills the resistance element storage part 11 with a filler 60. A sealing material 70 is applied to the upper surface of the material 60, and the lead wires 51, 51 connected to the resistance element 40 are drawn out to the outside of the case 10, and a groove sealing material 70 is used to waterproof the part where the lead wires 51, 51 are drawn out. It is constructed by applying sealants 81 and 85. In the following description, "upper" refers to the direction in which the sealing material 70 is viewed from the case 10, and "lower" refers to the opposite direction.

FIG. 4 is a diagram showing the case 10, in which FIG. 4(a) is a perspective view, FIG. 4(b) is a sectional view taken along line AA in FIG. 4(c), FIG. d) is a sectional view taken along line BB in FIG. 4(c). As shown in these figures, the case 10 is made of ceramic in the shape of a square prism, and has a substantially rectangular concave resistance element storage part 11 on its upper surface (top surface) 10a, and the bottom surface 10c of the case 10 is provided with a resistance element storage part 11 in the shape of a rectangular concave shape. An object to be heated (not shown) that is heated by the device 1 is used as the surface to be abutted.

The resistor element storage part 11 is formed in a size and shape that can accommodate the resistor element 40, and has a substantially U-shaped cross section as shown in FIG. 4(b). An opening 13 for the element storage portion 11 is provided. Furthermore, resistive element positioning parts 19, 19 are provided at both longitudinal ends of the inner bottom surface of the resistive element storage part 11 so as to protrude from the inner bottom surface and form stepped parts.

Lead wire insertion grooves 15, 15 are formed in the upper sides of both side surfaces 10e, 10f in the longitudinal direction of the case 10 in the shape of a concave groove (substantially U-shaped). The lead wire insertion grooves 15, 15 communicate with the storage portion 11, and the groove openings 17, 17 at the upper ends thereof communicate with the opening 13. The width of the lead wire insertion groove 15 is approximately the same as the outer diameter of the lead wire 51. Further, the inner bottom surface 21 of the lead wire insertion groove 15 is formed in a semicircular arc shape with an inner diameter dimension and shape that is approximately the same as the outer diameter dimension and shape of the lead wire 51.

The resistance element (fixed resistor) 40 is constructed by winding a resistance wire around the outer periphery of a cylindrical insulating rod, covering both ends of the resistance wire with metal caps 41, 41, and then inserting an electric wire 53 drawn out from the lead wires 51, 51, 53 is sandwiched between the caps 41, 41, and in this state, the outer peripheral surfaces of the caps 41, 41 are caulked. It goes without saying that the structure of the resistance element 40 is not limited to the structure of this embodiment.

In this embodiment, powder cement is used as the filler 60. Powder cement is a powder made by coating multiple types of insulating powder with different particle sizes (silica stone powder in this example) with varnish, and by applying heat, the varnish is melted and the powders are bonded together. They are bonded together and solidified into one piece when cooled.

The sealing material 70 and the groove-sealing sealing materials 81 and 85 are silicone resin (silicon rubber).

Next, a method for manufacturing the resistor 1 will be explained. 2 and 5 to 8 are explanatory diagrams of a method for manufacturing the resistor 1, and FIGS. 5 to 8 show cross sections corresponding to FIG. 4(d). First, as shown in FIG. 5, groove-sealing sealants 81, 81 are applied to the inner bottom surfaces 21, 21 of both lead wire insertion grooves 15, 15 of the case 10, and dried. As a result, an elastic sealing layer 15A (see FIG. 9) is formed on the inner bottom surface 21.

Next, as shown in FIGS. 2 and 6, the resistance element 40 is stored in the resistance element housing 11 through the opening 13 of the case 10, and at this time, the pair of lead wires 51 connected to both ends of the resistance element 40 are , 51 are inserted (press-fitted) into the lead wire insertion grooves 15, 15 of the case 10, respectively. At this time, the resistance element 40 is inserted and positioned between the pair of resistance element positioning parts 19, 19. Also, at this time, both lead wires 51, 51 come into elastic contact with the seal layer 15A (see FIGS. 6 and 9). Unlike the ceramic surface of the case 10, the seal layer 15A has elasticity and a smooth surface, so it easily adheres to the lead wire 51.

Next, as shown in FIG. 7, a filler 60 is filled into the housing portion 11 housing the resistance element 40. Then, as shown in FIG. At this time, both lead wire insertion grooves 15, 15 are also filled with the filler material 60. Then, the filler 60 is heated and dried to bond and integrate the powders, and then cooled and solidified. This seals the resistance element 40.

Next, as shown in FIG. 8, a groove-sealing sealing material 85 is placed above the lead wires 51, 51 on both sides 10e, 10f of the case 10, at a position that closes each lead wire insertion groove 15, 15. Apply. Next, as shown in FIG. 8, a sealing material 70 is applied so as to cover the upper surface of the filler 60 on the opening 13 and groove opening 17 sides, and is allowed to air dry. Resistor 1 is thus completed. Note that the above assembly procedure is only one example, and it goes without saying that assembly may be performed using various other assembly procedures.

The assembled resistor 1 is mounted, for example, on the outer peripheral surface of a water pipe of a heat exchanger for a water heater so that its bottom surface (mounted portion) 10c is in contact with the outer circumferential surface of a water pipe. When electricity is applied between the pair of lead wires 51, 51, the resistance element 40 is heated, the water pipe is heated, and freezing thereof is prevented.

As explained above, in the resistor 1, the sealing material 70 is applied so as to cover the upper surface of the opening 13 side of the filler 60 filled in the resistance element storage part 11 of the case 10. Intrusion of liquid or moisture into the case 10 can be reliably prevented, and insulation of the resistance element 40 inside the case 10 can be reliably maintained. In particular, in this embodiment, the waterproofness of the powder cement used as the filler 60 cannot be said to be better than that of liquid cement. Since the filling material made of powder cement is hardened in a rough state inside, it has lower insulation properties than liquid cement, and water and moisture easily enter, and therefore the effect of the sealing material 70 is large. Further, when powder cement is used as the filler 60, the surface thereof is likely to be scraped, but since the surface is covered with the sealing material 70, the problem of the scraping can be solved.

Further, in the resistor 1, the upper surface of the filler 60 filled in the lead wire insertion groove 15 on the groove opening 17 side is also covered by the sealing material 70, so that liquid or Can prevent moisture from entering.

Further, in the resistor 1, the groove sealing sealant 81 is applied to the inner bottom surface 21 of the lead wire insertion groove 15, and the lead wire 51 is placed on the inner bottom surface 21 of the lead wire insertion groove 15. Since the filling material 60 is filled, when the lead wire 51 is inserted into the lead wire insertion groove 15, the lead wire 51 can be easily and reliably brought into close contact with the groove sealing seal material 81 (seal layer 15A). , a minute gap does not occur between the inner bottom surface 21 of the lead wire insertion groove 15 and the lead wire 51. Thereby, it is possible to more effectively prevent liquid or moisture from entering into the resistance element storage section 11. That is, when powder cement is used as the filler 60 and the groove sealing sealant 81 is not applied, the contact between the inner bottom surface 21 of the lead wire insertion groove 15 and the lead wire 51 is greater than when liquid cement is used. It is difficult for the filler 60 to enter the gap created between the gaps, increasing the possibility that liquid or moisture will enter from the gap, but by applying the groove sealing sealant 81 (sealing layer 15A), the above-mentioned In this way, this possibility can be prevented.

In addition, in the resistor 1, the groove-sealing sealing material 85 closes the lead wire insertion groove 15 above the lead wire 51, so that liquid or moisture does not infiltrate into the resistance element storage portion 11 from the lead wire insertion groove 15 side. can be prevented even more effectively.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the claims and the technical idea described in the specification and drawings. It is possible. Note that any shape, structure, or material that is not directly described in the specification or drawings is within the scope of the technical idea of the present invention as long as it achieves the action and effect of the present invention. For example, in the above embodiment, the lead wire insertion grooves 15, 15 are provided on both side surfaces 10e, 10f in the longitudinal direction of the case 10, but the lead wire insertion groove may be provided on only one side surface. Two lead wire insertion grooves may be provided on one side surface. Alternatively, only one lead wire insertion groove may be provided, and two lead wires may be inserted into this one lead wire insertion groove. Furthermore, three or more lead wire insertion grooves may be provided and the lead wires may be inserted into each of these grooves. Further, the resistor according to the present invention is not limited to a resistor for a heater, and may be applied to a resistor used for various purposes other than a heater. Further, in the above embodiment, powder cement is used as the filler, but the resistor may be constructed using liquid cement instead. Furthermore, the embodiments described above and shown in the figures can be combined with each other as long as there is no contradiction in purpose, structure, etc. In addition, the above description and the contents of each figure, even if only a part thereof, can be an independent embodiment, and the embodiment of the present invention is an embodiment that combines the above description and each figure. It is not limited to.

1 Resistor 10 Case 11 Resistance element housing 13 Opening 15 Lead wire insertion groove 17 Groove opening 21 Inner bottom surface 40 Resistance element 51 Lead wire 60 Filler 70 Sealing material 81, 85 Groove sealing seal material

Claims (2)

A resistor configured by storing a resistance element in a resistance element storage part provided in a case, filling the resistance element storage part with a filler, and further pulling out a lead wire connected to the resistance element outside the case,
An opening for the resistive element housing is provided on the upper surface of the case,
and providing a lead wire insertion groove on at least one side of the periphery of the resistor element housing portion of the case, and connecting the groove opening to the opening,
Applying a groove-sealing sealant to the inner bottom surface of the lead wire insertion groove,
Inserting a resistance element into the resistance element housing through the opening, inserting the lead wire into the lead wire insertion groove from the groove opening , and placing the lead wire on the groove sealing seal material. The resistor is characterized in that the resistor element storage portion is filled with the filler material while the resistor element is placed in place , and a sealant is further applied to cover the upper surface of the filler material on the opening side. The resistor according to claim 1,
The filler is also filled in the lead wire insertion groove,
The resistor is characterized in that the sealing material is also applied to the upper surface of the filler filled in the lead wire insertion groove on the groove opening side.

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